JPH02156052A - Manufacture of hard aluminum alloy sheet - Google Patents

Abstract

PURPOSE:To manufacture a hard Al alloy sheet reduced in ear rate and excellent in formability by subjecting an ingot of an Al-Mn-Mg alloy with a specified composition to homogenizing treatment and to hot rolling and then subjecting the resulting plate to warm rolling under specified conditions and to cold rolling, while applying process annealing to the above between the cold rolling stages. CONSTITUTION:An ingot of an Al alloy having a composition containing, by weight, 0.5-1.5% Mn, 0.5-2.0% Mg, and one or >=2 kinds among 0.2-0.7% Fe, 0.1-0.5% Si, 0.05-0.5% Cu, 0.01-0.3% Cr, 0.05-1.0% Zn, and 0.005-0.15% Ti is heated at 500-600 deg.C for 1hr to undergo homogenizing treatment and hot-rolled without delay so as to be worked into a metal plate, e.g., of 1.6-7.0mm thickness. Subsequently, the resulting hot rolled plate is warm-rolled at 150-200 deg.C or cold- rolled, while warm-rolled between the cold rolling stages, and then, process annealing and final cold rolling are applied to the above, by which a metal sheet of about 0.4mm final sheet thickness can be formed.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to the production of aluminum alloy plates, more specifically, they have a low selvage rate, excellent formability, and are particularly suitable for beverage cans (DI cans).
The present invention relates to a method of manufacturing an aluminum alloy hard plate suitable for. (Prior Art) Aluminum beverage cans are widely used for beer, carbonated drinks, and the like, and are formed and manufactured using drawing and ironing (DI processing) as the main processing. The aluminum material used is Al-Mn-, which has excellent DI processability and strength.
Mg-based 3004 alloy hard material is common. Another characteristic required of aluminum beverage cans is that they have minimal occurrence of deep-draw ears. This is to prevent a decrease in yield, and also because materials with a high occurrence of ears may cause subsequent processing defects, and there is a strong demand for materials with less occurrence of ears. (Problem M to be Solved by the Invention) As described above, suppression of ear formation is important, and various manufacturing methods that reduce ear formation have been reported. For example, Japanese Patent Publication No. Sho 62-54183 proposes a method in which MnAQs is dissolved in solid solution. However, since this method requires high temperature and long time for solution treatment, there is a problem that it promotes deterioration of the quality of the plate surface. Incidentally, the occurrence of ears is determined by the abundance ratio of cubic texture and rolling texture. Conventionally, in cold-rolled aluminum alloy hard materials, ears are generated in a direction of 45° with respect to the rolling direction after drawing. Especially Al2-Mn-Mg
In the case of intermediate annealing type alloys (cold rolling → annealing → cold rolling), the edge after drawing is already 45° after intermediate annealing.
Therefore, in a hard material that is subsequently cold rolled, the selvedge in the 45° direction becomes higher. Therefore, it is necessary to lower the 45° direction selvedge after intermediate annealing as much as possible. One method is to combine two intermediate annealing steps, which the present inventors proposed in Japanese Patent Application No. 117888/1988. However, this method requires cold rolling with light reduction after the first intermediate annealing, which inevitably increases the number of cold rolling by one bus, which is a problem in terms of cost. The present invention has been made in order to solve the problems of the prior art described above, and has a low selvage ratio and excellent moldability, and in particular has a DI
The object of the present invention is to provide a method for manufacturing an aluminum alloy hard plate material suitable for cans. (Means for solving the problem of blood pressure) In order to achieve the purpose of reducing heat, the inventors of the present application conducted various tests on ways to reduce the number of baths applied after the first intermediate annealing in the previously proposed method. As a result, by using a new method other than the method of performing intermediate annealing twice,
They discovered a manufacturing method that reduces the 5° directional selvage. That is, 1. The method for manufacturing an aluminum alloy hard plate material according to the present invention includes Mn: 0.5 to 1.5% and Mg: o, 5
~2.0%, further Fe:0.2~0°7%, S
i: 0.1-0.5%, Cu: 0.05-0.5%, C
Contains one or more of r: 0.01 to 0.3%, Zn: 0.05 to 1.0%, and Ti: 0.005 to 0.15%, with the remainder being Al and unavoidable. A consisting of impurities
l The alloy ingot is subjected to homogenization heat treatment held at a temperature of 500 to 60°C for 1 hour or more, then hot rolled, and then
At least the final bath in rolling up to intermediate annealing is 15
It is characterized by performing warm rolling at 0 to 280°C, and further performing intermediate annealing and cold rolling. The present invention will be explained in more detail below. (Function) As mentioned above, the present invention is a method that does not require intermediate annealing twice.In short, it is a method of increasing the 0-90° direction selvedge after intermediate annealing, and it is a method that increases the recovery of the rolled M weave before intermediate annealing. This is a way to control the That is, it utilizes warm rolling. First, the reason for limiting the chemical composition of the Al alloy in the present invention will be explained. Mn is an element effective in solid solution strengthening. However, 0
．． If it is less than 5%, the strength is insufficient. - On the other hand, if it exceeds 1.5%, the strength will be too high, depending on the content of other elements, and in combination with Fe, a huge intermetallic compound (M n Fe ) A Q s will be formed. and promotes a decrease in moldability. Therefore, the amount of Mn is 0.5-1.5%
The range shall be . Like Mn, Mg is an element that is effective in solid solution strengthening. However, if it is less than 0.5%, the strength is insufficient. On the other hand, if it exceeds 2.0%, the strength becomes too high, although it depends on the content of Mn and other elements. This can cause cracks to occur during rolling and product processing. Therefore, the Mg amount is in the range of 0.5 to 2.0%. The above Mn and Mg are essential components, but in addition, Fe and SL
, Cu, Cr, Zn, and Ti. Fe is an element that affects crystal grains and ear ratio during recrystallization.If eFa is less than 0.2%, the crystal grains will become coarser.
If it exceeds 0.7%, it will lead to a decrease in moldability, and if it exceeds 0.7%, it will result in a high porosity, and further, (Mn, Fe)Al
1, forming giant intermetallic compounds, resulting in processing problems. Therefore, Fei is set in the range of 0.2 to 0.7%. Si is an element that affects the selvage rate and castability, and 0.
If it is less than 1%, the Fe/Si ratio will be high, leading to a high ear rate.
Moreover, when it exceeds 0.5%, casting cracks are likely to occur. Therefore, the amount of Si is set in the range of 0.1 to 0.5%. Cu is an element that is effective in solid solution strengthening, but 0.05
If it is less than 0.5%, the strength will be insufficient, while if it exceeds 0.5%, it will lead to a decrease in corrosion resistance. Therefore, the amount of Cu is set in the range of 0.05 to 0.5%. Cr is also an element that is effective in improving strength. However, if it is less than 0.01%, the strength is insufficient, and if it exceeds 0.3%, a giant intermetallic compound of Al-Mn-Cr is formed, which inhibits formability. Therefore, Cr
The amount is in the range of 0.01-0.3%. Zn is an element that is effective in improving formability. However, if it is less than 0.05%, the effect is small;
, if it exceeds 0%, the amount added is useless because no effect can be obtained. Therefore, the amount of Zn is 0.05 to 1.
The range is 0%. Ti is an element that is effective in refining the ingot. However, if it is less than 0.005%, the effect is small, and if it exceeds 0.15%, it tends to form nonmetallic inclusions, leading to a decrease in formability. Therefore, the amount of Ti is 0.00
It is in the range of 5 to 0.15%. Note that the above Al alloy may contain inevitable impurities contained in the base metal, but these impurities are allowed as long as they do not impede the effects of the present invention. Next, manufacturing conditions in the present invention will be explained. The Al alloy having the above composition is melted and cast by a conventional method, and casting is generally performed by DC casting. After casting, it is cut into appropriate sizes and solidified. - For boat fishing, the surface cutting amount is 5IllI or more on one side. A homogenization heat treatment is then performed to reduce segregation within the ingot and facilitate subsequent hot rolling. If the soaking temperature is less than 500°C, neither effect will be sufficient, and the soaking temperature is preferably 550°C or higher. Furthermore, if the temperature exceeds 600°C, burning is likely to occur. Since soaking for less than 1 hour is insufficient, the homogenization heat treatment is carried out at 500 to 600°C (preferably 550 to 600°C).
00°C) for 1 hour or more. After the homogenization heat treatment, it is immediately hot rolled. There are no particular restrictions on the conditions at this time, but preferably the hot rolling start temperature is 500'C or higher, the hot rolling end temperature is 280C or higher, and the plate thickness is 1.6 to 7.01. After hot rolling, warm rolling or cold rolling including warm rolling is performed, and further intermediate annealing and cold rolling are performed. First, warm rolling, which is the most characteristic feature of the present invention, will be explained. The purpose of warm rolling is to properly recover the rolled structure before the subsequent intermediate annealing, and this recovery leads to an increase in the cubic texture that increases the 0-90° direction edge in the subsequent intermediate annealing. If the warm rolling temperature is less than 150°C, the amount of recovery is small and the subsequent intermediate annealing has little effect on increasing the cubic texture, and if it exceeds 280°C, recrystallization proceeds immediately after the rolling. In this case, annealing is performed after cold rolling, which has no effect on increasing the cubic texture. Therefore, warm rolling needs to be performed in a temperature range of 150 to 280°C. Although it is preferable that all rolling before intermediate annealing be warm rolling, it has been confirmed that even just one final bath is effective. Furthermore, as a method of warm rolling, a method of rolling after heating in a continuous annealing furnace is preferable. After warm rolling or after cold rolling including warm rolling, intermediate annealing and cold rolling are performed.The annealing method here is not particularly regulated, but rapid heating heat treatment is recommended for grain refinement and productivity improvement. is preferable, in which case the heating and cooling rate is 100°C
If it is less than /win, it will have the opposite effect. Furthermore, heating at a temperature of less than 400° C. makes recrystallization difficult in a short period of time, but heating at a temperature exceeding 600° C. tends to cause burning. Furthermore, if the retention time exceeds 10 m1n, it is not preferable for any of them. Therefore, intermediate annealing is performed at a heating/cooling rate of 100°C/win or higher.
It is preferable to maintain the temperature at 0° C. within 10 m1n. The final step is cold rolling, which is effective in improving strength, and is preferably performed at a rolling rate of 30% or more. In addition,
If necessary, final annealing (100 to 200°C) may be performed, and this is particularly effective in improving stretchability. (Example) Next, an example of the present invention will be shown. Lost pod Al-1,05%Mn-1,20%Mg-0,22%C
u-0,26%5i-0,43%Fe-0,20%Zn
58 to an Al alloy ingot (50++ ua thickness) with a composition of
It was subjected to homogenization heat treatment at 0° C. for 4 hours and immediately hot rolled to a thickness of 5 m. Thereafter, rolling was performed under the conditions shown in Table 1, followed by annealing and cold rolling to give a product board thickness of 0.4 mm. Table 2 shows the material properties (mechanical properties, selvage ratio) of the obtained material. In addition, the ear ratio is blank diameter 68.7mmφ, punch diameter 4
Drawing was carried out under the conditions of 0@lφ (drawing ratio 1.67), and the value is shown as the difference between the peaks and valleys divided by the average height. The ear percentage is preferably less than 3%. This example shows the influence of temperature during one bath of warm rolling before annealing. From Table 2, the warm rolling temperature is 150-280℃
It can be seen that examples Na 3 to Na 4 of the present invention, which fall within the range of , have lower ears than the other examples. In addition, in order to investigate the formability, the elongation property was evaluated by the Eligsen test (method A), and the results were 5 and 1 for both the invention example and other examples.
l1ra, and no difference was observed.

[Left below]

11 Colors A hot-rolled plate (thickness: 5 am) produced in the same manner as in Example 1 was warm-rolled and/or cold-rolled to a thickness of 1°0IaI11 according to the bus schedule shown in Table 3. ,
Next, annealing and cold rolling were performed under the conditions shown in the same table, and the influence of the amount of warm rolling and its schedule was investigated. The results are shown in Table 3. From Table 3, it can be seen that warm rolling before annealing needs to be performed at least in the final bath as shown in Examples A to C of the present invention. On the other hand, although the comparative example is an example in which warm rolling was performed in the middle, no effect on reducing the selvedge ratio was observed.Also, almost no change in mechanical properties was observed in any of the examples, and Example 1
This is almost the same as the present invention measurement 4.

[Left below]

(Effects of the Invention) As detailed above, according to the present invention, the chemical composition and manufacturing conditions are regulated in the production of aluminum alloy hard plate materials, and the rolling process is particularly performed in which warm rolling is performed before annealing.
The effect of improving yield and reducing defects during processing due to the low selvage is remarkable. In addition, this manufacturing process has little effect on strength and can obtain sufficient properties in terms of moldability, making it suitable for DI cans. Patent applicant Hisashi Nakamura, patent attorney representing Kobe Steel, Ltd.

Claims (1)

[Claims] Contains Mn: 0.5 to 1.5% and Mg: 0.5 to 2.0% in weight% (the same applies hereinafter), and further Fe: 0.2
~0.7%, Si: 0.1-0.5%, Cu: 0.05
~0.5%, Cr:0.01~0.3%, Zn:0.0
5 to 1.0% and one or more of Ti: 0.005 to 0.15%, with the remainder being Al and unavoidable impurities. After homogenization heat treatment held at a temperature of 1 hour or more, hot rolling is performed, and then, during rolling up to intermediate annealing, at least the final bath is warm rolled at 150 to 280°C, and further intermediate annealing and cold rolling are performed. A method for producing an aluminum alloy hard plate material.